T-mobile service in Mexico City

Hi Everyone, I'm going to be moving to Mexico City and was thinking of switching to T-mobile from AT&T because of being able to use my US number in both countries. Is anyone out there using T-mobile in Mexico City and if so how is the service. T-mobile where I live isn't the best but they support wifi calling so I think I can get by with it. My main concern is how is in Mexico?